I have not yet been to this, but I must must go. Every July 4th, the towns of Stinson and Bolinas have a tug of war over the channel that separates the two towns. Despite being yards away from each other, the towns have very different feels (to say the least). That is what makes this event that much more fun.

A good writeup of the 7/4 event at the Marin Independent Journal; some highlights:

At the beach, a reputed 200-pound weight requirement for Bolinas tuggers may have made the difference, but Stinson partisans complained that a celebrant was offering free food stamps, whale blubber steaks and intoxicants to energize the Bolinas tugging team. Race officials said it was a case of sour grapes. “It was a fair match,” said Mike Bagley, an official who monitored fruitless efforts by both the Stinson men and women teams.

Every year the tug-of-war provides a chance for the two towns to symbolically spar. Bolinas has a reputation for tapping into its population of hardy, outdoorsy hippies, while Stinson is known for unabashedly using power and influence to recruit outside help.
…
According to local lore, Stinson has imported brute pulling strength in the form of 500 pound Samoans, the Berekely rowing team and, one year, a jeep, which resulted in a broken arm and the suspension of the contest for several years. This year, seven members of the Golden Gate rugby team, collectively weighing in at more than two tons, tossed a rugby ball around on the sidelines, keeping warm while awaiting their chance to pull Stinson to glory.